Does it make sense to open multiple portfolios with a different risk index in Endowus & Stashaway?

There are different risk profiles within Endowus and Stashaway - I personally dont see a reason why you want to do so from a risk perspective.

Unless you have a different view on the appropriateness of the different portfolios. Personally I would not want my low risk portfolios to be exposed to any currency risk so doing a 100% bond portfolio with Endowus, which is FX hedged, makes more sense.

Hope this helps!

If they are portfolios for different goals sure.

For example a 30yr retirement portfolio will look very different to a 5yr home and reno objective portfolio.

If they are for the same goal, then it makes no sense because you're not sticking to the risk strategy provided.